Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 2: Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
- 3: The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed.
- 4: Tests for other subsystem malfunctions within the control module used by the Variable Effort Steering (VES) system.
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Install a scan tool. Does the scan tool power up? | Go to Step 2 | Go to SCAN TOOL DOES NOT POWER UP in Data Link Communications |
| 2 | NOTE: The BCM/ESC stores the DTCs scan tool data and special functions. However, the scan tool menu to access variable effort steering is located in chassis. Turn ON the ignition, with the engine OFF. Attempt to establish communication with the Electronic Suspension Control (ESC) Module, vehicles equipped with Real Time Damping (RTD), or the Body Control Module (BCM), vehicles W/O RTD. Does the scan tool communicate with the ESC module, or BCM? | Go to Step 3 | Go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in Data Link Communications |
| 3 | Select the ESC module, or BCM Display DTCs function on the scan tool. Does the scan tool display any DTCs that begin with a "U"? | Go to DIAGNOSTIC TROUBLE CODE (DTC) LIST in Data Link Communications | Go to Step 4 |
| 4 | Does the scan tool display any BCM, or RTD, if equipped DTCs? | Go to DIAGNOSTIC TROUBLE CODE (DTC) LIST in Body Control System, or DIAGNOSTIC TROUBLE CODE (DTC) LIST in Real Time Damping | Go to Step 5 |
| 5 | Does the scan tool display any VES DTCs? | Go to Diagnostic Trouble Code (DTC) List | System OK |
Diagnostic System Check - Variable Effort Steering
The numbers below refer to the step numbers on the diagnostic table.
- 2: Tests if the sensor is within the valid voltage range.
- 3: Tests for the proper operation of the circuit in the high voltage range.
- 4: Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.
- 5: Tests for a short to ground and an open in the 5 volt reference circuit.
- 7: Test for a short to voltage, a high resistance, or an open circuit.
- 14: The control module must be calibrated when replaced.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Steering Controls Schematics | ||||
| 1 | If DTC C0870 is present perform the diagnosis for that DTC before proceeding. Did you perform the Variable effort Steering Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Variable Effort Steering | |
| 2 | Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, observe the steering wheel position signal 1/signal 2 data parameter in the suspension Control Module data list. Does the scan tool indicate that the steering wheel position signal 1/signal 2 data parameter is within the specified range? | 0.35-4.7 V | Go to TESTING FOR INTERMITTENT AND POOR CONNECTIONS | Go to Step 3 |
| 3 | Turn OFF the ignition. Disconnect the steering wheel position sensor harness connector. Turn ON the ignition, with the engine OFF. With a scan tool, observe the steering wheel position signal 1/signal 2 data parameter. Does the scan tool indicate that the steering wheel position signal 1/signal 2 data parameter is greater than the specified value? | 4.7 V | Go to Step 4 | Go to Step 8 |
| 4 | Turn OFF the ignition Connect a 3 amp fused jumper wire between the signal 1/signal 2 circuit and the low reference circuit of the steering wheel position sensor harness connector. Turn ON the ignition, with the engine OFF. With a scan tool, observe the steering wheel position signal 1/signal 2 data parameter. Does the scan tool indicate that the steering wheel position signal 1/signal 2 data parameter is less than the specified value? | 0.35 V | Go to Step 5 | Go to Step 9 |
| 5 | Turn OFF the ignition. Disconnect the fused jumper wire. Connect a 3 amp fused jumper wire between the 5 volt reference circuit and the signal 1/signal 2 circuit of the steering wheel position sensor harness connector. Turn ON the ignition, with the engine OFF. With a scan tool, observe the steering wheel position signal 1/signal 2 data parameter. Does the scan tool indicate that the steering wheel position signal 1/signal 2 data parameter is greater than the specified value? | 4.7 V | Go to Step 7 | Go to Step 6 |
| 6 | Test the 5 volt reference circuit of the steering wheel position sensor for a short to ground or an open. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | |
| 7 | Test the 5 volt reference circuit of the steering wheel position sensor for a short to voltage, a high resistance, or an open. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 11 | |
| 8 | Test the signal 1/signal 2 circuit of the steering wheel position sensor for a short to ground. Refer to TESTING FOR SHORT TO GROUND and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | |
| 9 | Test the signal 1/signal 2 circuit of the steering wheel position sensor for a short to voltage, a high resistance, or an open. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 10 | |
| 10 | Test the low reference circuit of the steering wheel position sensor for a high resistance, a short to voltage or an open. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | |
| 11 | Inspect for poor connections at the harness connector of the steering wheel position sensor. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 13 | |
| 12 | Inspect for poor connections at the harness connector of the Suspension Control Module. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 14 | |
| 13 | Replace the steering wheel position sensor. Refer to Steering Wheel Position Sensor or Steering Shaft Lower Bearing Replacement Did you complete the replacement? | Go to Step 15 | ||
| 14 | IMPORTANT: After replacement, use the scan tool to perform the setup procedure located under Special Functions (F8: Recalibration) for the suspension control module. Replace the suspension control module. Refer to ELECTRONIC SUSPENSION CONTROL MODULE REPLACEMENT (TAHOE/YUKON/ESCALADE) or ELECTRONIC SUSPENSION CONTROL MODULE REPLACEMENT (ESCALADE EXT) in Real Time Damping.Did you complete the replacement? | Go to Step 15 | ||
| 15 | Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTCs as specified in the supporting text. Does the DTC reset? | Go to Step 2 | System OK | |
| IMPORTANT |
|---|
| After replacement, use the scan tool to perform the setup procedure located under Special Functions (F8: Recalibration) for the suspension control module. |
DTC C0470 or C0506
The numbers below refer to the step numbers on the diagnostic table.
- 2: Tests if the sensor is within the valid voltage range.
- 3: Tests if the sensor is internally shorted to ground.
- 4: Tests if the signal circuit is shorted to ground
- 5: Tests if the 5 volt reference circuit is short to voltage or open.
- 14: Program the BCM after replacement.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Steering Controls Schematics | ||||
| 1 | Did you perform the Variable Effort Steering Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Variable Effort Steering | |
| 2 | Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, observe the steering wheel position sensor data parameter in the Electronic Variable Orifice data list. Does the scan tool display the steering wheel position sensor data parameter is within the specified range? | 0.35-4.7 V | Go to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems | Go to Step 3 |
| 3 | Turn OFF the ignition. Disconnect the steering wheel position sensor harness connector. Turn ON the ignition, with the engine OFF. With a scan tool, observe the steering wheel position sensor data parameter. Does the scan tool indicate that the steering wheel position sensor data parameter is greater than specified value? | 0.0 V | Go to Step 4 | Go to Step 8 |
| 4 | Turn OFF the ignition. Connect a 3 amp fused jumper wire between the signal circuit and the low reference circuit of the steering wheel position sensor harness connector. Turn ON the ignition, with the engine OFF. With a scan tool, observe the steering wheel position sensor data parameter. Does the scan tool indicate that the steering wheel position sensor data parameter is less than specified value? | 0.35 V | Go to Step 5 | Go to Step 9 |
| 5 | Turn OFF the ignition. Disconnect the fused jumper wire. Connect a 3 amp fused jumper wire between the 5 volt reference circuit and the signal circuit of the steering wheel position sensor harness connector. Turn ON the ignition, with the Engine OFF. With a scan tool, observe the steering wheel position sensor data parameter. Does the scan tool indicate that the steering wheel position sensor data parameter is greater than the specified value? | 4.7 V | Go to Step 7 | Go to Step 6 |
| 6 | Test the 5 volt reference circuit of the steering wheel position sensor for a short to ground. Refer to TESTING FOR SHORT TO GROUND and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | |
| 7 | Test the 5 volt reference circuit of the steering wheel position sensor for a short to voltage or an open. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 11 | |
| 8 | Test the signal circuit of the steering wheel position sensor for a short to ground. Refer to TESTING FOR SHORT TO GROUND and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | |
| 9 | Test the signal circuit of the steering wheel position sensor for a short to voltage or an open. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 10 | |
| 10 | Test the low reference circuit of the steering wheel position sensor for a short to voltage or an open. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | |
| 11 | Inspect for poor connections at the steering wheel position sensor harness connector. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 13 | |
| 12 | Inspect for poor connections at the BCM harness connector. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 14 | |
| 13 | Replace the steering wheel position sensor. Refer to Steering Wheel Position Sensor or Steering Shaft Lower Bearing Replacement . Did you complete the replacement? | Go to Step 15 | ||
| 14 | Replace the BCM. Refer to BODY CONTROL MODULE REPLACEMENT in Body Control Systems. Did you complete the replacement? | Go to Step 15 | ||
| 15 | Use the scan tool in order to clear the DTCs. Operate the vehicle within the conditions for running the DTC as specified in the supporting text. Does the DTC reset? | Go to Step 2 | System OK | |
DTC C0472 or C0473
The numbers below refer to the step numbers on the diagnostic table.
- 2: Tests the EVO solenoid circuits in there active state using the scan tool.
- 3: Tests if the resistance of the EVO solenoid is within the specified range.
- 5: Tests if the EVO solenoid supply circuit is shorted to voltage inside the control module.
- 6: Tests if the EVO solenoid supply circuit is shorted to voltage
- 9: Program the BCM/ESC Module after replacement.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Steering Controls Schematics | ||||
| 1 | IMPORTANT: If DTC C0501 is also set, perform the diagnostic procedure for C0501 before proceeding. Did you perform the Variable Effort Steering Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Variable Effort Steering . | |
| 2 | Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the EVO solenoid ON and OFF. Does the EVO solenoid turn ON and OFF with each command? | Go to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems | Go to Step 3 | |
| 3 | Turn OFF the ignition. Disconnect the EVO solenoid harness connector. Measure the resistance of the EVO solenoid. Does the resistance measure within the specified value? | 11-13 ohms | Go to Step 4 | Go to Step 8 |
| 4 | Inspect for poor connections at the EVO solenoid harness connector. Did you find and correct the condition? | Go to Step 10 | Go to Step 5 | |
| 5 | Probe the EVO solenoid supply circuit at the solenoid harness connector with a test lamp connected to ground. Turn ON the ignition, with the engine OFF. Does the test lamp turn on when the ignition is turned ON? | Go to Step 9 | Go to Step 6 | |
| 6 | Does the test lamp remain on continuously with the ignition ON or OFF? | Go to Step 7 | Go to Step 10 | |
| 7 | Test the EVO solenoid supply circuit for a short to voltage. Refer to TESTING FOR A SHORT TO VOLTAGE and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 9 | |
| 8 | Replace the EVO solenoid. Refer to Power Steering (PS) Solenoid Actuator, Discharge Fitting Replacement . Did you complete the replacement? | Go to Step 10 | ||
| 9 | Replace the BCM/ESC module. Refer to BODY CONTROL MODULE REPLACEMENT in Body Control Systems, or ELECTRONIC SUSPENSION CONTROL MODULE REPLACEMENT (TAHOE/YUKON/ESCALADE) or ELECTRONIC SUSPENSION CONTROL MODULE REPLACEMENT (ESCALADE EXT) in Real Time Damping. Did you complete the replacement? | Go to Step 10 | ||
| 10 | Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset? | Go to Step 2 | System OK | |
| IMPORTANT |
|---|
| If DTC C0501 is also set, perform the diagnostic procedure for C0501 before proceeding. |
DTC C0495
The numbers below refer to the step numbers on the diagnostic table.
- 2: Tests the EVO solenoid circuits in there active state using the scan tool.
- 3: Tests if the BCM/ESC module is providing voltage to the EVO solenoid.
- 4: Tests for an open in the control circuit to the EVO solenoid.
- 5: Tests if voltage is constantly being applied to the EVO solenoid.
- 13: Reprogram the BCM/ESC module when replacement is necessary.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Steering Controls Schematics | ||||
| 1 | Did you perform the Variable Effort Steering Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Variable Effort Steering | |
| 2 | Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the EVO solenoid ON and OFF. Does the EVO solenoid turn ON and OFF with each command? | Go to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems | Go to Step 3 | |
| 3 | Turn OFF the ignition. Disconnect the EVO solenoid. Turn ON the ignition, with the engine OFF. With a test lamp connected to a ground probe the EVO solenoid supply circuit at the solenoid harness connector. With a scan tool, command the EVO solenoid ON. Does the test lamp turn ON with initial command? | Go to Step 4 | Go to Step 5 | |
| 4 | Connect a test lamp between the EVO solenoid supply circuit and the EVO solenoid control circuit of the solenoid harness connector. With a scan tool, command the EVO solenoid ON. Does the test lamp turn ON with initial command? | Go to Step 8 | Go to Step 10 | |
| 5 | Does the test lamp remain illuminated continuously with each command? | Go to Step 7 | Go to Step 6 | |
| 6 | Test the EVO solenoid supply circuit for a short to ground. Refer to TESTING FOR SHORT TO GROUND and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 9 | |
| 7 | Test the EVO solenoid supply circuit for a short to voltage or an open. Refer to CIRCUIT TESTING and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 9 | |
| 8 | Inspect for poor connections at the harness connector of the EVO solenoid. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 11 | |
| 9 | Inspect for poor connections at the harness connector of the BCM/suspension control module. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 13 | |
| 10 | Repair the control circuit of the EVO solenoid. Refer to WIRING REPAIRS in Wiring Systems. Did you complete the repair? | Go to Step 14 | ||
| 11 | Measure the resistance of the EVO solenoid. Does the resistance measure within the specified value? | 11-13 ohms | Go to Step 13 | Go to Step 12 |
| 12 | Replace the EVO solenoid. Refer to Power Steering (PS) Solenoid Actuator, Discharge Fitting Replacement Did you complete the replacement? | Go to Step 14 | ||
| 13 | Replace the BCM/ESC module. Refer to BODY CONTROL MODULE REPLACEMENT in Body Control Systems, or ELECTRONIC SUSPENSION CONTROL MODULE REPLACEMENT (TAHOE/YUKON/ESCALADE) or ELECTRONIC SUSPENSION CONTROL MODULE REPLACEMENT (ESCALADE EXT) in Real Time Damping. Did you complete the replacement? | Go to Step 14 | ||
| 14 | Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset? | Go to Step 2 | System OK | |
DTC C0496, C0498, or C0499
The numbers below refer to the step numbers on the diagnostic table.
- 2: Tests the EVO solenoid circuits in there active state using the scan tool.
- 3: Tests if the EVO solenoid resistance is with in specified range.
- 4: Tests for poor connections at the EVO solenoid harness connector.
- 5: Tests if the control module is supplying a ground to the EVO solenoid.
- 6: Tests for a short to ground on the EVO solenoid control circuit.
- 12: Program the ESC module/BCM after replacement.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Steering Controls Schematics | ||||
| 1 | Did you perform the Variable Effort Steering Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Variable Effort Steering | |
| 2 | Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the EVO solenoid from OFF to ON. Does the EVO solenoid turn OFF and ON with each command? | Go to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems | Go to Step 3 | |
| 3 | Turn OFF the ignition. Disconnect the EVO solenoid. Measure the resistance of the EVO solenoid. Does the resistance measure within the specified value? | 11-13ohms | Go to Step 4 | Go to Step 11 |
| 4 | Inspect the EVO solenoid harness connector control and supply circuits for poor connections. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 5 | |
| 5 | Probe the EVO solenoid control circuit at the solenoid harness connector with a test lamp connected to battery voltage. Turn ON the ignition, with the engine OFF. Does the test lamp turn ON when the ignition is turned ON? | Go to Step 7 | Go to Step 6 | |
| 6 | Does the test lamp remain on continuously with the ignition ON or OFF? | Go to Step 8 | Go to Step 9 | |
| 7 | Turn ON the ignition, with the engine OFF. With the scan tool, command the EVO solenoid OFF. Does the test light turn OFF with initial command? | Go to Step 13 | Go to Step 8 | |
| 8 | Test the EVO solenoid control circuit for a short to ground. Refer to TESTING FOR SHORT TO GROUND and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 12 | |
| 9 | Test the EVO solenoid control circuit for a short to voltage or an open. Refer to TESTING FOR A SHORT TO VOLTAGE and WIRING REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 10 | |
| 10 | Inspect the Suspension Control Module/BCM harness connector control circuit for poor connections. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 12 | |
| 11 | Replace the EVO solenoid. Refer to Power Steering (PS) Solenoid Actuator, Discharge Fitting Replacement . Did you complete the replacement? | Go to Step 13 | ||
| 12 | Replace the ESC module/BCM. Refer to ELECTRONIC SUSPENSION CONTROL MODULE REPLACEMENT (TAHOE/YUKON/ESCALADE) or ELECTRONIC SUSPENSION CONTROL MODULE REPLACEMENT (ESCALADE EXT) in Real Time Damping, or BODY CONTROL MODULE REPLACEMENT in Body Control System. Did you complete the replacement? | Go to Step 13 | ||
| 13 | Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset? | Go to Step 2 | System OK | |
DTC C0501, C0503, or C0504
The numbers below refer to the step numbers on the diagnostic table.
- 2: Tests if the malfunction exists in the Steering Wheel Position Sensors centered position.
- 3: Tests if the malfunction exist in the Steering Wheel Position Sensors left turn range.
- 4: Tests if the malfunction exist in the Steering Wheel Position Sensors right turn range.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Steering Controls Schematics | ||||
| 1 | Did you perform the Variable Effort Steering Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Variable Effort Steering | |
| 2 | Install a scan tool. Turn ON the ignition, with the engine on. Center the steering wheel. With a scan tool, observe the Steering Wheel Position Sensor signal 1 and Steering Wheel Position Sensor signal 2 data parameters in the RTD/EVO data list. Does the scan tool display the signal 1 and signal 2 data parameters at the specified value? | Signal 1: 4.0 V signal 2: 2.0 V | Go to Step 3 | Go to Step 5 |
| 3 | Slowly turn the steering wheel to full left lock while observing the signal 1 and signal 2 data parameters. Do the signal 1 and signal 2 data parameters change state in synchronization with each other and reach the specified value? | Signal 1: 2.5 V signal 2: 4.5 V | Go to Step 4 | Go to Step 5 |
| 4 | Slowly turn the steering wheel to full right lock while observing the signal 1 and signal 2 data parameters. Do the signal 1 and signal 2 data parameters change state in synchronization with each other and reach the specified value? | Signal 1: 1.6 V signal 2: 1.6 V | Go to TESTING FOR INTERMITTENT AND POOR CONNECTIONS in Wiring Systems | Go to Step 5 |
| 5 | Inspect for poor connections at the harness connector of the Steering Wheel Position Sensor. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS in Wiring Systems. Did you find and correct the condition? | Go to Step 7 | Go to Step 6 | |
| 6 | Replace the Steering Wheel Position Sensor. Refer to Steering Wheel Position Sensor or Steering Shaft Lower Bearing Replacement . Did you complete the replacement? | Go to Step 7 | ||
| 7 | Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset? | Go to Step 2 | System OK | |
DTC C0521
Variable Effort Steering System Description and Operation
The Variable Effort Steering (VES) system controls the amount of steering effort needed to steer the vehicle as vehicle speed and steering wheel position and turning speed changes. The Body Control Module (BCM) or Electronic Suspension Control (ESC) module, vehicles equipped with Real Time Damping (RTD), controls an electronic Variable Orifice (EVO) solenoid located in the power steering pump's output fluid orifice. The solenoid consists of a pintle valve which moves in and out of the orifice, regulating power steering fluid flow. The BCM/ESC module varies the amount of steering effort by commanding more or less current to the solenoid. At low speeds, no current is commanded and the pintle is fully retracted which provides maximum fluid flow and maximum steering assist for easy turning and parking maneuvers. At high speeds, more current is commanded to the solenoid and the pintle moves closer to the orifice, decreasing fluid flow, providing firmer steering (road feel) and directional stability. The VES system uses the Steering Wheel Position sensor input to calculate lateral acceleration during abrupt driving maneuvers. The system also uses the Vehicle Speed Sensor (VSS) signal from the Powertrain Control Module (PCM) via a class 2 serial data circuit. The control module is constantly monitoring these inputs to achieve the desired current to the EVO solenoid. The BCM/ESC module has the ability to detect malfunctions within the VES system. Any malfunctions detected will cause the EVO outputs to be disabled. Some VES system malfunctions may cause the SERVICE STABILITY SYSTEM warning message to be displayed on the Instrument Panel Cluster (IPC) message center.
NOTE: The BCM/ESC stores the DTCs scan tool data and special functions. However, the scan tool menu to access variable effort steering is located in chassis.